Possible Triggering of Molecular Mimicry by Environmental Pollution.

The 'molecular mimicry theory' states that foreign antigens introduced during infection can activate autoreactive T or B cells, leading to autoimmune diseases. However, despite a decrease in infectious burden, autoimmune disease incidence is on the rise globally. To address this paradox, we analyzed the impact of benzo[a]pyrene (BaP) on the autoimmune-prone mouse strain MRL. We found that BaP induced the expression of genes, the protein products of which showed homology to bacterial pathogens, in the MRL spleen and kidneys. Based on our findings, we propose the hypothesis that environmental pollutants may 'mimic' the impact of pathogen invasion on the immune system in autoimmune-susceptible individuals.